A beginners question: I run a VPS with CentOS 6.7 i686. It runs very smooth and fast for 2 years. But I have some problems that some software does not run anymore on PHP 5.3.3 The thought of upgrading to PHP scares me a little. I hope I can gather some expert advise. For PHP 5.6.* , does that tutorial looks workable? Would it even be possible to jump to PHP 7.0.* ? https://www.zerostopbits.com/how-to-upgrade-php-5-3-to-php-5-6-on-centos-6-7/
be careful if you use php 7.0 because only ispconfig 3.1 works with this version. I can recommend the remi repo.